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Biomedical subjects

M Kobayashi

Publications and source records attributed to M Kobayashi.

At least 37 records · Page 2Linked to original sources
PubMed2006

Surgical correction of ventricular septal defect with aortic regurgitation in a dog.

An 8-month-old entire Miniature Dachshund, weighing 4.2 kg, was presented for examination following delvelopment of a cough. Ventricular septal defect had been diagnosed tentatively in its infancy on the basis of a cardiac murmur detected by auscultation and echocardiography. Echocardiography using a B mode right parasternal long-axis view showed a defect at the atrioventricular junction and a thickened cusp of the aortic valve prolapsing into the defect. Colour-flow Doppler showed shunt blood flow across the defect at the level of the atrioventricular junction, from left to right. The sinus of Valsalva was dilated, with turbulent blood flow. Aortic regurgitation was also observed. Cardiac catheterisation studies confirmed the diagnosis of a supracristal ventricular septal defect with aortic regurgitation. Despite medication with digoxin, enalapril and aminophylin, started from the first admission, left ventricular internal dimensions gradually increased, and fractional shortening of the left ventricle gradually decreased. Surgery, with the aid of extracorporeal circulation, to close the ventricular septal defect, was performed 1 year after the initial examination. The aortic valve was left untreated. Postoperatively, the systolic murmur disappeared. Shunt flow from the left to the right ventricle was no longer observed on echocardiography, however there was still a small amount of aortic regurgitation during diastole visualised with colour-flow Doppler echocardiography. The prolapse of the cusp of the aortic valve on B-mode echocardiography was no longer observed and thickening of the cusp had not progressed. Left ventricular function measurement using M mode echocardiography showed a reduced left ventricular volume overload with reduced left ventricular internal dimensions and increased fractional shortening. The cough was relieved and no follow-up medication was scheduled. Early surgical closure of the ventricular septal defect improved the patient's condition and controlled prolapse and thickening of the aortic valve.

Animals↗
PubMed2006

Closed reduction for traumatic posterior dislocation of the shoulder using the 'lever principle': two case reports and a review of the literature.

Traumatic posterior dislocation of the shoulder is frequently missed because of its rarity and the absence of characteristic symptoms. Several signs should be emphasised: an overlap of the humeral head and glenoid rim in a true anteroposterior view and the light-bulb sign in the anteroposterior view. To make an accurate and early diagnosis, use of multidirectional radiographs combined with computed tomography is recommended. Closed reduction was successfully performed under general anaesthesia using the DePalma method with slight modification--the lever principle--by pushing the medial side of the upper arm laterally to adduct the shoulder as far as possible. The dynamics of the lever principle make it a safer and more effective method of achieving a closed reduction of a posterior dislocation of the shoulder than the conventional method of solely pushing the humeral head anteriorly, especially in patients with locking of the glenohumeral joint and impression fractures.

Aged↗
PubMed2006

Efficacy of adjuvant chemotherapy using oral fluorinated pyrimidines for curatively resected gastric cancer: a meta-analysis of centrally randomized controlled clinical trials in Japan.

Adjuvant chemotherapy for gastric cancer has been extensively explored in Japan since the 1950s, and a combination of oral fluorinated pyrimidines (o-FP) and mitomycin C (MMC) has been mainly utilized for adjuvant chemotherapy. However, there is no sufficient evidence for the efficacy of adjuvant therapy. Therefore, we assessed the efficacy of o-FPs over surgery alone (control) by means of a meta-analysis of Japanese centrally randomized controlled clinical trials conducted between 1980 and 2005. For inclusion in this study, studies had to compare adjuvant chemotherapy for curatively resected gastric cancer with surgery alone, mainly targeting o-FP, and central randomization designed to comply with contemporary standards for clinical trials in Japan. For the 4 trials that met the eligibility criteria, the estimated hazard ratio was 0.73 (95%CI=0.60-0.89). Our findings show that in Japan adjuvant chemotherapy using o-FP for long-term maintenance therapy appears to be effective for gastric cancer patients after curative resection.

Antibiotics, Antineoplastic↗
PubMed2006

The estrogen-responsive adrenomedullin and receptor-modifying protein 3 gene identified by DNA microarray analysis are directly regulated by estrogen receptor.

Recent studies have revealed that hundreds of genes in the uterus are activated by estrogen. Their expression profiles differ over time and doses and it is not clear whether all these genes are directly regulated by estrogen via the estrogen receptor. To select the genes that may be regulated by estrogen, we treated mice with several doses of estrogen and searched for those genes whose dose-response expression pattern mirrored the uterine growth pattern. Among those genes, we found that the dose-dependent expression of the adrenomedullin (ADM) gene correlated well with the uterotrophic effect of estrogen. ADM expression is induced early after estrogen administration and is restricted to the endometrial stroma. The spatiotemporal gene expression pattern of ADM was similar to that of receptor-modifying protein 3 (RAMP3). RAMP3 is known to modify calcitonin gene-related receptor (CRLR) so that it can then serve as an ADM receptor. Chromatin immunoprecipitation assays indicated that the estrogen receptor binds directly to the ADM promoter region and RAMP3 intron after estrogen administration. It was also shown that neither the ADM nor RAMP3 gene could be activated in estrogen receptor-alpha-null mouse. Although uterine ADM expression has been reported to occur in the myometrium, our observations indicate that estrogen-induced ADM is also expressed in the uterine stroma and that such variable, spatiotemporally regulated ADM expression contributes to a wider range of biological effects than previously expected.

Adrenomedullin↗
PubMed2006

Effect of bubble flow velocity on drag-force and shear stress working on submerged hollow fibre membrane.

This study is aimed at elucidating the mechanism by which rising air bubbles induce shear stress on hollow fibre membrane surfaces. Shear stress on hollow fibre membrane surfaces (laterally-set and vertically-set) caused by aeration was measured directly using a two-direction load sensor. In the laterally-set hollow fibre module, time-averaged upward-direction shear stress on the membrane surface was compared to theoretical shear stress values considering the effect of water flow on membrane surface. Measured time-average shear stress values were almost 200 times larger than theoretical values implying strong interactions between bubbles and solid surface. In the vertically-set membrane module, velocity measurement of bubble flow using laser Doppler velocimeter revealed that drag force working on membrane surface was closely related to upward-direction water velocity. Also fluctuation of drag force and shear force on membrane surface was found to be related to velocity fluctuation (turbulence).

Bioreactors↗
PubMed2006

Molecular evidence supports that Anopheles anthropophagus from China and Anopheles lesteri from Japan are the same species.

The Hyrcanus group of Anopheles consists of many related species, of which An. sinensis, An. lesteri, and An. anthropophagus are known as malaria vector species. It is not possible to identify these species morphologically in the adult and larval stages. Nucleotide sequence alignment of 2nd internal transcribed spacer (ITS2) regions from 4 specimens of An. lesteri collected in Japan, 2 specimens of An. anthropophagus collected in China, and 1 specimen of An. sinensis collected in Korea were sequenced and compared. Sequences of ITS2 regions varied only at 4 sites between An. lesteri and An. anthropophagus, and individual variations among each An. lesteri and An. anthropophagus were found at 5 and 7 sites, respectively, whereas sequences varied at 161 sites between An. lesteri and An. sinensis. This molecular evidence strongly supports that An. lesteri from Japan and An. anthropophagus from China are the same species.

Animals↗
PubMed2006

Cost-effectiveness of Liple (LipoPGE1) for arteriosclerosis obliterans patients in Japan: an economic evaluation using the EQ-5D instrument.

AIM: This study was conducted to evaluate the health-related quality of life (HRQOL) and cost-effectiveness of LipoPGE(1) when added to the conventional treatment of arteriosclerosis obliterans (ASO) patients. The research design consisted of a before and after-treatment study without comparison groups. We collected data from May 1999 through July 2001 at 473 institutions located throughout Japan. The subjects were ASO patients who experienced pain at rest or had ulcers of the extremities. METHODS: The observation period was a 2-month period that commenced with the start of administration of LipoPGE1. The HRQOL score (utility value) was obtained from the EQ-5D instrument, and the incremental cost-effectiveness ratio was calculated on the basis of quality-adjusted life years (QALYs). RESULTS: The mean utility value for the 2 months after the start of the administration of LipoPGE(1) was 0.672, and it was a significantly higher (P<0.0001) than the 0.616 before administration of LipoPGE(1). The incremental cost-effectiveness ratio was 18,807 US dollar/QALY assuming that drug efficacy persisted for 1 year after the end of LipoPGE1 therapy, and 75,227 dollar/QALY assuming a duration of just 3 months. CONCLUSIONS: We concluded that when LipoPGE1 is added to the conventional treatment of ASO patients, the HRQOL of the patient improves, and it is highly cost-effective.

Adolescent↗
PubMed2005

Laparoscopic lymph node dissection around the inferior mesenteric artery for cancer in the lower sigmoid colon and rectum: is D3 lymph node dissection with preservation of the left colic artery feasible?

BACKGROUND: When we perform laparoscopic lymph node dissection around the inferior mesenteric artery (IMA), we preserve the left colic artery (LCA) to maintain the blood supply to the proximal sigmoid colon. In this study, we present our laparoscopic D2 and D3 lymph node (LN) dissection technique and evaluate its applicability and safety. METHODS: We performed LN dissection on 23 rectal and lower sigmoid colon cancer cases from April 2002 to December 2004. For D3 LN dissection, the incision to the mesosigmoid extends to just before the root of the IMA, which is exposed with an ultrasonic cutting and coagulating surgical device to avoid bleeding. Then, the arterial wall is exposed with a dissecting electrocautery spatula down to the LCA, at least 2 cm of which is exposed. Adipose tissue surrounding the IMA and inferior mesenteric vein is dissected. For D2 LN dissection, we partially expose the IMA to confirm the location of the LCA. RESULTS: The mean times taken for D2 and D3 LN dissections were 36.2 and 68.2 min, respectively. Both procedures took longer in male patients. There was a trend for the procedure overall to take less time in female patients. However, D2 dissection took significantly longer in male than female patients (p < 0.05). In women, D3 dissection took significantly longer than D2 (p < 0.05), but this trend was not seen in men. Increased experience among surgeons with this procedure was associated with significantly faster LN dissections in men (p < 0.05), but not in women (p = 0.493). Pearson product moment analysis identified a relationship between body mass index (BMI) and the time taken for D2 LN dissection (r = 0.765), but not D3 LN dissection (r = 0.158). There was no treatment-related morbidity with this technique. CONCLUSIONS: This method was safe and feasible for all patients in this series, but takes longer to perform in male patients.

Aged↗
PubMed2005

A quantitative analysis of lymphatic vessels in human breast cancer, based on LYVE-1 immunoreactivity.

This study was undertaken to determine the highly sensitive method for detecting tumour lymphatic vessels in all the fields of each slide (LV), lymphatic microvessel density (LMVD) and lymphatic vessel invasion (LVI) and to compare them with other prognostic parameters using immunohistochemical staining with polyclonal (PCAB) and monoclonal antibodies (MCAB) to the lymphatic vessel endothelial hyaluronan receptor-1 (LYVE-1), and the pan-endothelial marker factor VIII in a series of 67 human breast cancers. In all LYVE-1-stained sections, LV (some of which contained red blood cells) were frequently found localised in extralobular stroma, dermis, connective tissue stroma and adjacent to artery and vein, but were rare within the intralobular stroma or the tumour body (3/67 cases) or areas of widespread invasion. In contrast small blood vessels were observed in intra- and extralobular stroma in the factor VIII-stained sections. Quantitation of vessel numbers revealed that LYVE-1/PCAB detected a significantly larger number of LV than either H&E or LYVE-1/MCAB (P<0.0001). LYVE-1/PCAB detected LVI in 25/67 cases (37.3%) and their presence was significantly associated with both lymph node metastasis (chi(2)=4.698, P=0.0248) and unfavourable overall survival (OS) (P=0.0453), while not relapse- free survival (RFS) (P=0.2948). LMVD had no influence for RFS and OS (P=0.4879, P=0.1463, respectively). Our study demonstrates that immunohistochemistry with LYVE-1/PCAB is a highly sensitive method for detecting tumour LV/LVI in breast cancer and LVI is a useful prognostic indicator for lymphatic tumour dissemination.

Adult↗
PubMed2005

Onset of steroid-induced osteonecrosis in rabbits and its relationship to hyperlipaemia and increased free fatty acids.

OBJECTIVES: To clarify the initial onset time of osteonecrosis after the start of steroid treatment and its relation to the onset of abnormal lipid metabolism. METHODS: Animal models were prepared by administering methylprednisolone to rabbits using five different steroid regimens. RESULTS: A single, acute ischaemic event suggested by the frequency, size or number of necrotic foci within the proximal femur was not different among the groups. Histological evidence of osteonecrosis first occurred 1-2 weeks after initial steroid administration. At the same time there were significantly abnormal elevations in serum lipids, which persisted for between 1 and 2 weeks after the initial corticoid treatment. Triglycerides, total cholesterol and free fatty acids were markedly elevated in all groups; these lipid abnormalities were significantly present in the rabbits with osteonecrosis but not in the rabbits without osteonecrosis. CONCLUSIONS: This study shows that (i) osteonecrosis appears in rabbits shortly after corticoids are first administered, and (ii) osteonecrosis in rabbits is chronologically associated with the onset of hyperlipaemia and increased free fatty acids. This supports the occurrence of intraosseous fat embolism as a cause of osteonecrosis.

Animals↗
PubMed2005

Apnea, glial apoptosis and neuronal plasticity in the arousal pathway of victims of SIDS.

Of 27,000 infants whose sleep-wake characteristics were studied under the age of 6 months, 38 died unexpectedly 2-12 weeks after the sleep recording in a pediatric sleep laboratory. Of these infants, 26 died of sudden infant death syndrome (SIDS), and 12 of definitely identified causes. The frequency and duration of sleep apneas were analysed. Sleep recordings and brainstem histopathology were studied to elucidate the possible relationship between sleep apnea and neuropathological changes within the arousal system. Immunohistochemical analyses were conducted using tryptophan hydroxylase (TrypH), a serotonin synthesizing enzyme, and growth-associated phosphoprotein 43 (GAP43), a marker of synaptic plasticity. The terminal-deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) method was used for apoptosis. The pathological and physiological data were correlated for each infant. In the SIDS victims, statistically significant positive correlations were seen between the number of TrypH-positive neurons in the dorsal raphe nucleus of the midbrain and the duration of central apneas (p = 0.03), between the number of TUNEL-positive glial cells in the pedunculopontine tegmental nucleus (PPTN) and the average number of spines in GAP43-positive neurons in the PPTN (p = 0.04). These findings in the dorsal raphe nucleus of the midbrain and PPTN, that play important roles in the arousal pathway suggest a possible link between changes in arousal and SIDS.

Apoptosis↗
PubMed2005

Effects of salt concentration on the yield stress of sodium montmorillonite suspension.

The yield stress of Na-montmorillonite suspension in an electrostatically dispersed state was studied to confirm the validity of previously proposed equation for the dependency of the yield stress on the volume fraction of clay and ionic strength. In the derivation of the equation, it is assumed that (1) clay layers array in parallel, and (2) the yield stress is equivalent to the strength of electrostatic repulsion when it reaches the yield stress. Measurements of the yield stress were performed with the vane method, varying the volume fraction of clay, phi, under controlled ionic strength for the region of 0.008<phi<0.023 and 10(-2)<NaCl<10(-5) M. Experimental data qualitatively agreed with theoretical predictions; however, quantitative differences were found to range from 0.1 to 1000 times. This discrepancy can be eliminated if we introduce a correction factor. Reasonable agreement was obtained when the factor was proportional to n(0)(-0.256).

Journal Article↗
PubMed2005

Thyroid lesions and dioxin accumulation in the livers of jungle crows (Corvus macrorhynchos) in urban and suburban Tokyo.

Wild jungle crows (Corvus macrorhynchos) captured from three different areas of Tokyo were examined to evaluate environmental contamination of dioxins. In addition to the pathologic examination of their whole body, accumulation of dioxins, mRNA expression of the aryl hydrocarbon receptor (AhR), and pentoxyresorufin-O-depenthylase (PROD) activity in the liver were determined. Marked histopathologic changes were observed in the thyroid glands, especially in the crows from the urban downtown area. Levels of dioxins and their toxic equivalents (TEQs) and AhR mRNA expression in the livers of the crows from the urban area were higher than those from the suburban area. There was a high correlation between the levels of TEQs and PROD activity. The results of the present study demonstrated that jungle crows possess AhR-mediated toxicologic pathways similar to those of mammals and suggest the possibility that the thyroidal changes observed in the adult crows from the urban areas are one of the toxic manifestations resulting from exposure to dioxins and other environmental chemicals.

Age Factors↗
PubMed2005

Anomalous vortex motion in the quantum-liquid phase of amorphous MoxSi1-x films.

We measure, in real time (t), the fluctuating component of the flux-flow voltage V(t), deltaV(t) identical withV(t)-V0, about the average V0 in the vortex-liquid phase of amorphous MoxSi1-x films. For the thick film, deltaV(t) originating from the vortex motion is clearly visible in the quantum-liquid phase, where the distribution of deltaV(t) is asymmetric, indicative of large velocity and/or number fluctuations of driven vortices. For the thin film the similar anomalous vortex motion is observed in nearly the same (reduced-)temperature regime. These results suggest that vortex dynamics in the low-temperature liquid phase of thick and thin films is dominated by common physical mechanisms, presumably related to quantum effects.

Journal Article↗
PubMed2005

Inhibition of endogenous SHIP2 ameliorates insulin resistance caused by chronic insulin treatment in 3T3-L1 adipocytes.

AIMS/HYPOTHESIS: SHIP2 is a physiologically important negative regulator of insulin signalling hydrolysing the PI3-kinase product, PI(3,4,5)P3, which also has an impact on insulin resistance. In the present study, we examined the effect of inhibiting the endogenous SHIP2 function on the insulin resistance caused by chronic insulin treatment. METHODS: The endogenous function of SHIP2 was inhibited by expressing a catalytically inactive SHIP2 (DeltaIP-SHIP), and compared with the effect of treatments designed to restore the levels of IRS-1 in insulin signalling systems of 3T3-L1 adipocytes. RESULTS: Chronic insulin treatment induced the large (86%) down-regulation of IRS-1 and the modest (36%) up-regulation of SHIP2. Subsequent stimulation by insulin of Akt phosphorylation, PKClambda activity, and 2-deoxyglucose (2-DOG) uptake was markedly decreased by the chronic insulin treatment. Coincubation with the mTOR inhibitor, rapamycin, effectively inhibited the proteosomal degradation of IRS-1 caused by the chronic insulin treatment. Although the coincubation with rapamycin and advanced overexpression of IRS-1 effectively ameliorated subsequent insulin-induced phosphorylation of Akt, insulin stimulation of PKClambda activity and 2-DOG uptake was partly restored by these treatments. Similarly, expression of DeltaIP-SHIP2 effectively ameliorated the insulin-induced phosphorylation of Akt without affecting the amount of IRS-1. Furthermore, the decreased insulin-induced PKClambda activity and 2-DOG uptake following chronic insulin treatment were ameliorated by the expression of DeltaIP-SHIP2 more effectively than by the treatment with rapamycin. CONCLUSIONS/INTERPRETATION: Our results indicate that the inhibition of endogenous SHIP2 is effective in improving the state of insulin resistance caused by chronic insulin treatment.

3T3 Cells↗
PubMed2005

Hippocalcin-deficient mice display a defect in cAMP response element-binding protein activation associated with impaired spatial and associative memory.

Hippocalcin is a member of the neuronal calcium sensor (NCS) protein family that is highly expressed in hippocampal pyramidal cells and moderately expressed in the neurons of cerebral cortex, cerebellum and striatum. Here we examined the physiological roles of hippocalcin using targeted gene disruption. Hippocalcin-deficient (-/-) mice displayed no obvious structural abnormalities in the brain including hippocampal formation at the light microscopic level. Deletion of hippocalcin did not result in up-regulation of the hippocalcin-related proteins; neural visinin-like Ca(2+)-binding proteins (NVP) 1, 2, and 3. The synaptic excitability of hippocampal CA1 neurons appeared to be normal, as estimated by the shape of field excitatory postsynaptic potentials elicited by single- and paired-pulse stimuli, and by tetanic stimulation. However, N-methyl-d-aspartate stimulation- and depolarization-induced phosphorylation of cAMP-response element-binding protein (CREB) was significantly attenuated in -/- hippocampal neurons, suggesting an impairment in an activity-dependent gene expression cascade. In the Morris water maze test, the performance of -/- mice was comparable to that of wild-type littermates except in the probe test, where -/- mice crossed the previous location of the platform significantly less often than +/+ mice. Hippocalcin-deficient mice were also impaired on a discrimination learning task in which they needed to respond to a lamp illuminated on the left or right side to obtain food reinforcement. No abnormalities were observed in motor activity, anxiety behavior, or fear learning. These results suggest that hippocalcin plays a crucial role in the Ca(2+)-signaling pathway that underlies long-lasting neural plasticity and that leads to spatial and associative memory.

Animals↗